servo retaining its position everytime i send some value - arduino

Question

i wanted to control my servo with bluetooth modue. I gave certain values for rotating it. but when i press those values the servo rotates but then retains it's original position and pc pc also make the sound of arduino board disconnecting because i powered the board with my pc(tried with powerbank also)
this is my code
#include <Servo.h>
Servo myservo;
int pos = 0;
char data = 0;
void setup() {
myservo.attach(9);
Serial.begin(9600);}
void loop(){
if(Serial.available() > 0){
data = Serial.read();
if(data == 'F'){
// for (pos = 0; pos <= 180; pos += 1) even this line dosent work
myservo.write(180);
delay(1);
}}
else if(data == 'B'){
// for (pos = 180; pos >= 0; pos -= 1) even this line dosent work
myservo.write(0);
delay(1);
}}
connections
servo
red wire -- 5v (not working in 3.3 v)
orange wire -- pin9
brown wire -- gnd
bluetooth (hc05)
5v -- 5v
gnd -- gnd
rx -- tx
tx -- rx

Answer 1

Your else if (data=='B'){ is in the wrong place - it's part of the if(Serial.available() > 0) { condition - instead of the if(data == 'F'){ condition. Notice the double }} in the line before.
I've corrected the code and reformated it so you can clearly see the matching opening and closing braces.
This works on Tinkercad Circuits passing commands through the serial monitor - so imagine it would work fine taking commands from bluetooth.
#include <Servo.h>
Servo myservo;
int pos = 0;
char data = 0;
void setup() {
myservo.attach(9);
Serial.begin(9600);
}
void loop() {
if(Serial.available() > 0) {
data = Serial.read();
if(data == 'F'){
for (pos = 0; pos <= 180; pos += 1) {
myservo.write(pos);
delay(1);
}
}
else if(data == 'B'){
for (pos = 180; pos >= 0; pos -= 1) {
myservo.write(pos);
delay(1);
}
}
}
}